We know one side of the smaller rectangle, 6ft. Therefore the longer side is 78/6 ft = 13ft.
The ratio of small to large side is 6:10, so the larger rectangles other length is (13 / 6) * 10 ft = 21.666... ft.
Thus the area of the larger rectangle is 21.666... * 10 = 216.666... ft^2, and hence to the nearest whole number it is 217 ft^2
